This is a good question. I have some original Telefunken smooth and ribbed plate 12AX7s that have tarnished pins. Does it help to remove that tarnish or just leave it alone? I have magic eraser and ProGold Deoxit.
@stevecham that's primarily why I asked - I too have fairly recently fitted NOS Telefunken tubes. I cleaned the slightly tarnished pins as good as I could (one tip I read was to use a very sharp craft nice & gently scrape the pins to expose a clean surface) wipe with a lint free cloth but not apply DeoxIT.
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